permutations and combinations2

There are 9 different books. a) How many ways to group them into 3 piles, such that there are 2 books in a pile, 3 books in another and 4 books in the remaining pile? b) How many ways to distribute the books to Gilbert, Howard and Ivan, such that one of them gets 2 books, another one gets 3 books and the remaining one gets 4 books? c) How many ways to group the books into 3 piles such that there are 3 books in each pile?